We report a study of electron proton collisions at very low Q2, corresponding to virtual photoproduction at centre of mass energies in the range 100–295 GeV. The distribution in transverse energy of the observed hadrons is much harder than can be explained by soft processes. Some of the events show back-to-back two-jet production at the rate and with the characteristics expected from hard two-body scattering. A subset of the two-jet events have energy in the electron direction consistent with that expected from the photon remnant in resolved photon processes.

We report results on ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}$ total and differential cross sections from threshold to 1.1-GeV $\ensuremath{\pi}\ensuremath{\pi}$ mass. These results have been obtained from a high-statistics experiment studying the reaction ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}n$ at 2.01 GeV/c incident ${\ensuremath{\pi}}^{\ensuremath{-}}$ momentum with the Chew-Low extrapolation method. The ${\ensuremath{\pi}}^{0}$'s have been detected and their momenta analyzed in a large-gap cylindrical spark chamber placed in a magnetic field. The results show three salient features: (i) A large $I=0$ production with ${\ensuremath{\sigma}}_{\mathrm{tot}}({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0})$ approaching the $S$-wave unitarity limit in the 550-750-MeV $\ensuremath{\pi}\ensuremath{\pi}$ mass region, without any narrow structure. (ii) A slow fall of ${\ensuremath{\sigma}}_{\mathrm{tot}}({\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0})$ in the region of 750-950-MeV $\ensuremath{\pi}\ensuremath{\pi}$ mass. This feature is not predicted by the "down" solution for the $I=0$ $S$-wave $\ensuremath{\pi}\ensuremath{\pi}$ phase shift which has been reported recently. (iii) The presence of $D$-wave effects above 850 MeV as indicated by our extrapolated angular distributions.

An accurate measurement of dσdΩ (π−p → ηn) at 1531 MeV total energy (expanded) up to l = 4 Legendre polynomials) requires reconsideration of previous angular distribution fits which were expanded only up to l = 2 and of subsequent partial-wave analysis. An energy-dependent partial-wave analysis has been performed here for pη∗ up to 450 MeV/c. In addition to the well-known S11 (1520 MeV) resonance, either the P11 (1532 MeV) or the P13 (1530 MeV) resonance is found to be strongly coupled to the η-n channel. In both cases, the P11 (1729 MeV) resonance is needed as is the weakly coupled D13 (1525 MeV) resonance. The decay states in the ηn channelare compared to the SU(3) and SU(6)W predictions.

π+π− ⇒ πoπo elastic and differential cross sections from threshold to 1 GeV ππ mass have been obtained by Chew‐Low extrapolation methods from the reaction π−p⇒πoπon at 2 GeV/c. We find large J = 0 production approaching the unitarity limit in the 450–750 MeV ππ mass. An energy‐independent phase shift analysis up to F waves using both the πoπo final state and the already known π±π±, π−πo, π+π− states (giving I = 0,1,2) verifies the overall consistency of the experimental data. Supplemented by the use of forward dispersion relations the phase shift analysis gives a unique solution characterized by the scattering lengths aoo = 0.67 and ao2 = 0.021 and by the presence of an ε (J = I = 0) of mass 940 MeV and width 180 MeV.

A K+p phase-shift analysis has been performed with the same methods as used for pion-nucleon scattering. Two kinds of solutions were found, both showing an anticlockwise half circle in P13 or S11. Their interpretation does not require the necessary existence of a resonance (Z∗).

A pion-nucleon elastic scattering phase shift analysis has been performed up to 2.8 GeV/c pion laboratory momentum. Recent experimental data have been included and the ‘continuity’ of the solution with energy have been investigated with special care.